Mereology and Modality: The Lumpl and Goliath Story

If one were to count all the things in Paris, it would be odd to count both the Eiffel Tower and the rusty, 19th century metal that constitutes it. After all, it seems crazy to believe that two distinct objects can occupy the exact same space at the exact same time. However, commonsense intuitions such as these, when considered alongside other well-accepted principles, entail some fairly troubling results; results that force philosophers to reject principles that seem to be true, at least on their face. One such philosopher, David Lewis, attempts to solve one aspect of the problem of Material Constitution while minimizing the blow to commonsense, by using his theory of Modal Realism. He undoubtedly salvages several “folk” assumptions, but at what costs?